(a) Field of the Invention
The present invention relates to a dye solution monitoring device and a dye solution controlling device for a dye-sensitized solar cell, more particularly, to a dye solution monitoring device and a dye solution controlling device for a dye-sensitized solar cell that may optimize dye adsorption in real time to manufacture a solar cell of high quality with high productivity, maximize utilization of expensive dye, and minimize the waste, thereby reducing production cost, and may manufacture a highly efficient battery, and a method applied to the devices.
(b) Description of the Related Art
Since a dye-sensitized nanoparticle titanium oxide solar cell was developed by Michael Gratzel et al., of EPFL (Ecole Polytechnique F d rale de Lausanne) at 1991, many studies thereon has been progressed. A dye-sensitized solar cell may replace the existing amorphous silicon solar cell because it has high efficiency and remarkably low manufacture cost compared to the existing silicon type solar cell, and unlike the silicon solar cell, it is a photoelectrochemical solar cell consisting of a dye molecule capable of absorbing visible light to generate electron-hole pairs and transition metal oxide transferring the produced electrons.
In general, a unit cell of a dye-sensitized solar cell includes upper and lower transparent substrates (generally, glass), a conductive transparent electrode made of transparent conductive oxide (TCO) respectively formed on the transparent substrates, a dye-adsorbed transition metal oxide porous layer on one conductive transparent electrode corresponding to a first electrode (working electrode), a catalyst thin film electrode (predominantly, Pt) on the other conductive transparent electrode corresponding to a second electrode (catalyst electrode), and electrolyte filled between the transition metal oxide (for example, TiO2) and the catalyst thin film electrode. Thus, the dye-sensitized solar cell basically consists of a working electrode substrate on which photoelectrode (TiO2) material including dyes receiving light to generate electrons attached thereto are coated, a catalyst electrode substrate supplying electrons, and electrolyte supplying electrons to oxidized dyes therebetween.
The efficiency and the production cost of the solar cell are largely influenced by the adsorption amount of the adsorption dyes having excellent properties on the transition metal oxide porous layer. Specifically, as the adsorption amount is high and the properties of the absorbed dyes are excellent, photoelectric efficiency of the solar cell increases, expensive dyes are efficiently used, and thus, waste ratio of non-adsorbed dyes is lowered to reduce production cost.
However, in the prior art, to increase adsorption rate, newly synthesized dye is adjusted to a concentration with best adsorption rate, to prepare a dye solution, and a cell of a solar cell is impregnated therewith. Thus, as an adsorption process progresses for a plurality of cells, the concentration changes to decrease adsorption rate, and the remaining dye solution should be discarded, and thus, waste ratio is high to cause serious waste of dyes. Therefore, to improve this, the concentration of a dye solution is controlled; however, light absorption coefficient is gradually lowered due to modification of dyes during the adsorption process compared to using of initial solution, and thus, manufacturing of an excellent solar cell may not be optimized only by concentration control, and in the case of manual concentration control, a dye adsorption process may not be continuously progressed to decrease productivity.
Accordingly, there is a need for development of dye solution monitoring device and method that may overcome the problems.